The present invention relates in general to apparatus for recording information from a master medium onto a slave medium, and more particularly to apparatus for recording information from a master medium onto a slave medium employing digital techniques.
Heretofore, duplicating equipment employed a continuous loop-bin tape storage device for the master tape reproducer. More specifically, the master tape was installed on a playback device with a temporary storage bin. The playback device advanced the master tape as an endless loop. Long rolls of magnetic tape were installed on each slave transport of the recording device. Each roll of magnetic tape installed on each slave transport of the recording device was of sufficient length to record a multiple of times the information stored on the endless loop magnetic tape. The slave tape moved at a speed which was s synchronous multiple of the original master. The master tape was advanced through the temporary storage bin a sufficient number of times to reproduce the information on a desired number of segments of each roll of slave tape, respectively. The recording of information on the slave tapes was performed at speeds which were the speed of recording information on the master tape or multiples of the speed of recording information on the master tape. Such a device had many draw-backs, such as tape breakage, head to tape contact wear, and tape wear. Additionally, the tape had abraded the playback head on the playback device. Such action had caused wearing on the playback head, which resulted in reducing the range of frequency responses for the system. The magnetic tapes had frequently snapped and were torn as they were transported into and out of the loop bin. As a consequence thereof, an operator had to stop the duplication process to repair the master tape, recue the slave tapes to the start of a tape point, and restart the duplication process.
Another apparatus for duplicating information from a master tape onto slave tapes employed a reel-to-reel master tape transport. Each slave tape respectively recorded the complete information from the master tape. The complete recording of the information contained on the master tape was followed by a rewinding of the master tape. Thus, each reproduced copy of the complete information from a master tape was followed by a rewinding of the master tape.
The loop-bin storage technique and the reel-to-reel technique were not suitable for the reduced time duplication of video recordings. Electrical problems and tape handling problems had prevented duplication of video tapes at any speed other than the master tape record speed.
Generally, tapes travelling at high speeds, such as 120 inches per second, reacted aerodynamically to the air pressure generated between the tape and the reproduce head. As a consequence thereof, the tape did not make intimate mechanical contact with the reproduce head. This action resulted in a reduction of the amplitude of the information signal from the master tape and a reduction in the frequency response of the duplication system.
Other problems realized from the loop-bin technique were tape flutter, oxide transfer from tape to reproduce head resulting in a loss of information from the master tape, and signal cross-talk as the tape travelled laterally across the reproduce head. This resulted in the coupling of adjacent channel information into the desired channel and the reduction of signal strength from the desired channel.